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Colonoscopy
A colonoscopy is the most reliable way to find colon cancer early, and the only test that can remove the polyps that cause it during the same appointment.
At a glance
20–30 minutes
That is the procedure itself. Allow about two hours at the clinic in total, for the assessment beforehand and recovery afterwards.
Covered by OHIP
The procedure is funded by OHIP for insured Ontario patients. There is a separate, voluntary fee for uninsured services, explained on your booking sheet.
Results before you leave
You are given your results verbally and in writing, including a colour photograph of what the endoscopist saw, on the day.
What a colonoscopy is
A colonoscopy is a visual examination of the inside of your large bowel. A long flexible tube called a colonoscope, roughly the thickness of a finger, is passed into the rectum and advanced along the colon. The scope carries a video camera that projects a magnified image of the bowel lining onto a screen.
It is used to remove polyps, to identify abnormalities including cancers, to stop bleeding, to take biopsies, and to investigate symptoms. Because polyps can be removed in the same sitting, a colonoscopy is both a test and a treatment.
Who should have one
Your doctor decides whether a colonoscopy is right for you. People are commonly referred because they:
- are due for routine colon cancer screening, generally from age 50
- have had a positive or abnormal FIT (stool) test result
- have a family history of colorectal cancer or polyps
- have noticed rectal bleeding, a change in bowel habits, or unexplained weight loss
- have unexplained iron deficiency anaemia
- are due for follow-up after polyps were removed previously
Had an abnormal FIT test?
An abnormal FIT result does not mean you have cancer. It means blood was detected and the next step is to look directly at the bowel. A colonoscopy is that next step, and your family doctor can refer you to us for it.
Preparing for it
The bowel has to be completely empty for the endoscopist to see the lining clearly. When we book your appointment we will tell you which of two preparations to follow, Peglyte or Pico-Salax, and send you the full instruction package.
The instructions cover which foods and drinks are permitted in the 48 hours beforehand and exactly when to take the laxative. The preparation always starts the day before your procedure.
Work out the exact times for your appointment, read the full preparation guide, or go straight to the instruction documents.
Not following the prep can cost you the appointment
If the bowel is not clean, the examination is unreliable and sizeable polyps can be missed. Where the view is inadequate the procedure has to be cancelled and rebooked, which means going through the preparation again. If any part of the instructions is unclear, call the clinic at 905-856-2626.
On the day
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Arrival and assessment
You will be asked to read and sign the consent form if you have not already. A nurse checks you in and reviews your medical history and medications.
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Sedation
An intravenous line is started so the physician can give you sedating medication to make you relaxed and drowsy. You may be awake during the procedure but are unlikely to remember the details. The clinic is usually supported by board-certified anaesthetists.
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The examination
Twenty to thirty minutes. Air is used to inflate the bowel so the lining can be seen, which can feel uncomfortable or crampy for short stretches. Polyps found are removed and sent for analysis.
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Recovery
Your pulse, breathing and blood pressure are checked as the sedation wears off. Feeling bloated or having some abdominal cramping afterwards is normal and settles.
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Results and going home
The endoscopist goes through the findings with you and gives you a written report with a colour photograph. A copy goes to your referring doctor within 24 hours.
Risks you should know about
Colonoscopy is a very safe procedure, but no procedure is entirely without risk. The figures we quote patients are:
| Risk | Approximate likelihood |
|---|---|
| Perforation of the bowel wall | About 1 in 1,000 |
| Bleeding, up to 10 days later, where a polyp has been removed | About 1 in 100 |
| A sizeable polyp or significant lesion being missed | Less than 5%, and higher if the bowel is not adequately cleaned |
These risks, and the benefits of the procedure, are set out in the consent form. You will be asked to read it and agree before your appointment is booked, and to sign it before the procedure takes place.
Afterwards
- You must not drive for 12 hours after sedation. Arrange for someone to drive you home. If you travel by bus or taxi, somebody must accompany you.
- Unless the physician tells you otherwise, you can go back to your normal diet straight away.
- Most people return to work the next day.
- Any follow-up you need is arranged by the endoscopist, who will look after you for anything found during the examination.
If you also need a gastroscopy
If you are having a colonoscopy and you have symptoms that warrant an upper endoscopy as well, the two can be arranged for the same visit. Follow the colonoscopy preparation instructions in that case. More about gastroscopy.
Bring an interpreter if you need one
If you have difficulty with English, please bring a friend or family member to interpret for you. Instructions are also available in Italian.
Ready to book?
We accept patients by physician referral only. Ask your family doctor, walk-in physician or specialist to fax our referral form to 905-856-2602.